Application of improved enzyme induced calcium carbonate precipitation (EICP) technology in surface protection of earthen sites

Abstract

Tabia is a common building material in ancient China. At present, there are few studies on protective materials for tabia ancient buildings, and the existing protective materials of earthen ruins have many problems. To study protective materials that are compatible with the tabia and have superior performance, sucrose and skimmed milk powder improved enzyme induced calcium carbonate precipitation (EICP) technology was applied to the surface protection of tabia relics. The results indicate that the effect of EICP modified by sucrose is better than that of skimmed milk powder. After being treated with 5% sucrose -EICP material, the surface hardness, salt corrosion resistance, weather resistance and water repellency of tabia samples can be increased by 12.7%, 550%, 300% and 512% respectively. The reason is that sucrose regulates the growth morphology of calcium carbonate crystals and provides nucleation sites for them. Moreover, sucrose has certain viscosity, which promotes the accumulation and cementation of calcium carbonate, and finally forms a dense protective layer on the surface of the tabia. Compared with loose calcium carbonate crystal formed by EICP treatment, the protective effect of sucrose improved EICP is significantly improved. Sucrose modified EICP technology can be used as an effective method for the protection of tabia relics and even ancient buildings.